SR 6/7: Albo 2013- sperm storage and cryptic female choice for nuptial gifts

Question 1

where nuptial gifts facilitate female mating what may females gain?

Answer 1

indirect benefits through prefered storage of sperm from gift giving males if they are a signal of quality

Question 2

what was the study species?

Answer 2

spider P.mirabilis

Question 3

what did the study quantify?

Answer 3

number of sperm stored in response to copulation with males with and without gift

Question 4

what did they assess the effect of gift presence and copulation duration on?

Answer 4

egg hatching success in uninterrupted matings with gift giving males

Question 5

what % higher egg hatching success was there for females who mated with gift giving males?

Answer 5

17%

Question 6

what did uninterrupted copulations result in?

Answer 6

increased sperm storage and egg hatching success

Question 7

how and under what conditions can the nuptial gifts be considered a male signal?

Answer 7

under +ve SS

by cryptic sperm storage

Question 8

what does giving gifts benefit to the males?

Answer 8

• longer copulations
• increased sperm transfer
• higher mating success
• more eggs fertilised

Question 9

what is cryptic mate choice?

Answer 9

SS during mating or post mating

Question 10

what can nutritious gifts be a signal for?

Answer 10

male quality in terms of good hunting ability

Question 11

what may gift giving be a target for and evolution of what will it favour?

Answer 11

sexually antagonistic coevolution

evolution of fake gifts

Question 12

what can internal processes resulting in fertilisation bias be mediated by?

Answer 12

both sexes

Question 13

why are there few studies on female cryptic sperm choice?

Answer 13

hard to disentangle male and female driven processes

Question 14

what is the gift that this spider species offers?

Answer 14

insect wrapped in silk that female feeds on during copulation

Question 15

how do males transfer sperm?

Answer 15

externally using pedipalps loaded with sperm

Question 16

where do females store sperm?

Answer 16

spermatheca storage organ

Question 17

how do males court?

Answer 17

offer gift in chelicerae whilst waving pedipalps

Question 18

what does the male do once the female has accepted the gift?

Answer 18

initiates sperm transfer inserting pedipalps into female genital tract

Question 19

what test was used for normal distribution of residuals

Answer 19

Shapiro wilk

Question 20

what test was used for homogeneity of variances?

Answer 20

Levene’s test

Question 21

what were generalised linear models used for?

Answer 21

to analyse sperm number, hatching success and effect of copulation duration on hatching success

Question 22

what was linear regression used for?

Answer 22

effect of copulation duration on number of sperm stored

Question 23

how did they calculate sperm count?

Answer 23

dissected female sperm storage organs and counted sperm under microscope

Question 24

what was found for sperm count? (2)

Answer 24

• if doesnt give give less sperm count and less stored in female genital tract
• most sperm stored when females mated with gift giving males uninterrupted

Question 25

how was hatching success calculated?

Answer 25

total eggs in first egg sac produced counted and success is the proportion of hatched eggs

Question 26

what is the relationship between copulation duration and hatching success?

Answer 26

positive

Question 27

where was hatching success highest?

Answer 27

gift giving groups with uninterrupted copulation

Question 28

what are the indirect benefits the female may gain? (2)

Answer 28

- by fisherian processes if produce sexy sons more likely to provide gifts - elevated offspring fitness if gift giving males pass on genes

Question 29

why was it suggested females select males based on their quality?

Answer 29

satiated males had higher mating and paternity success compared to starved males

Question 30

what does the data suggest sperm storage is at least partially under the control of?

Answer 30

female through cryptic sperm choice

Question 31

what may differential sperm storage be due to?

Answer 31

- preferential sperm uptake during mating | - post copulatory differential sperm selection

Question 32

how can males increase their fertilisation success through increasing sperm transfer? (4)

Answer 32

- longer copulation - higher rate of ejaculate transfer - increased sperm size - different types of sperm produced in 1 ejaculate

Question 33

what do males tailor the number of sperm in pedipalps to?

Answer 33

in response to being able to acquire a gift

Question 34

what is copulation duration positively correlated with?

Answer 34

nuptial feeding and gift quality

Question 35

which males can gain an advantage in sperm competition?

Answer 35

males that can offer nuptial gifts that take longer to consume

Question 36

how do both males and females benefit from sperm storage and longer copulations?

Answer 36

increased sperm transfer so higher paternity and indirect benefits to the female

Question 37

what acts to maintain selection for high quality gifts?

Answer 37

combination of cryptic female sperm storage favouring gift giving males and advantaged in sperm competition to those offering genuine gifts

Question 38

what was determined in the female sperm storage organs

Answer 38

the number of sperm

Question 39

what were each of these groups of males: a) NG males b) GT males c) G males

Answer 39

a) no gift and copulate without interruption b) gift and copulation terminated after 10 mins c) gift and uninterrupted copulation

Question 40

what differed among the 3 experimental groups?

Answer 40

number of sperm

Question 41

which group stored significantly higher sperm and had higher hatching success?

Answer 41

G males | with uninterrupted matings with gift giving males

Question 42

what are males copulating without gifts likely under selection pressure to do?

Answer 42

increase sperm transfer rate

Question 43

who controls copulation duration?

Answer 43

females

Question 44

what is expected if worthless gifts are given?

Answer 44

cryptic female choice